Valve system for centrifuges



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VALVE SYSTEM FOR CENTRIFUGES Filed Oct. 20, 1949 a Sheets-Sheet 1 .DDESSUPE Exs-musr $W.WW"F

Q T TOPNE Y5 1952 G. J. STREZYNSKI 2,616,621

VALVE SYSTEM FOR CENTRIFUGES Filed on. 20, 1949 a Sheets-Sheet 2 Nov. 4, 1952 G. J. STREZYNSK! VALVE SYSTEM FOR CENTRIFUGES 3 Sheets-Sheet 5 Filed Oct. 20, 1949 b 2 m a J 5 6 6 w e 6 f 0 4 5 5 HQ mm 6 M 5 J 6 m 0 M y \/./m A l J a 5 w w INVENTOP m S 5 mm mi 5%? J: Mm v/ 65 i atented Nov. 4, 1952 VALVE SYSTEM FOR CENTRIFUGES George J. Strezynski, Poughkeepsie, N. Y., as-

signor to The De Laval Separator Company, New York, N. Y., a corporation of New Jersey Application October 20, 1949, Serial No. 122,414

5 Claims. 1 This invention relates to centrifugal separators, and more particularly to an improved centrifuge of the type in which the centrifugal bowl is pro- .vided with valves for opening and closing outlets in the bowl periphery.

It is common practice to discharge separated solids or sludge from centrifugal bowls intermittently through peripheral outlets, by alternately opening and closing the outlets through the action of one or more valves in the peripheral part of the bowl. In some cases, the bowl is'provided with a series of valves, one for each peripheral outlet, and the valves are operated by a plunger which is moved axially of the bowl through a mechanical connection from outside the bowl, as disclosed in my Patent No. 2,291,117, dated July 28, 1942. Valve systems of this type as constructed heretofore have not been entirely satisfactory for several reasons, among which are their incapacity to operate quickly and reliably over long periods of time without repair or ad justment, their space requirements (which may place undesirable limitations on the bowl design), and their complexity. The problem of overcoming these deficiencies is complicated by the inherent characteristics of centrifugal bowls, such as their high speeds of rotation, the large centrifugal forces encountered, and the necessity for feeding, separating and discharging the materials without interference from or interfering with the peripheral valves and their operating mechanism.

The principal object of the present invention is to provide a centrifuge of the character described having an improved valve system which overcomes the above-mentioned disadvantages.

A centrifuge made according to the invention comprises a centrifugal bowl provided with peripheral outlets for discharging separated sludge or other solids separated as a heavier component. Mounted in the'bowl and concentric with its rotation'axis is an annular supporting member rotatable with the bowl and having circumferentially spaced radial slots. A plurality of levers are pivotally supported on this member in the slots, the inner ends of the levers being movable axially within the supporting member. A valve rod is connected at its inner end to each lever eccentrically with respect to the pivotal axis of the lever, and at the outer end of each rod is a valve element adapted to close one of the bowl outlets. Rotatable with the bowl in axial alignment with the annular supporting member is a sleeve containing a plunger which rotates with the sleeve. The plunger is slidable axially in the sleeve to operate the levers and thereby move the 2 valve rods radially inward so as to open the bow outlets. The rotating plunger is actuated by a non-rotating element disposed outside the bowl and engageable with one end of the plunger.

In one form of the invention, each lever has a pivoted eccentric which is surrounded by a strap or yoke connected to the corresponding valve rod. The eccentric is preferably recessed to receive the end of a screw threaded in the yoke and engagea'ble by a shoulder of the eccentric. In this way, the extent to which each bowl outlet is opened, upon actuation of the lever by the plunger, may be varied by adjusting the screw in the yoke of the corresponding valve rod.

In another form of the invention, each lever is pivotally mounted in one of the slots in the annular supporting member by means including a pin and a socket which can be separated by inward displacement of the lever from its slot, whereby the pin and socket are urged together by centrifugal force acting upon the lever. Thus, when the bowl is stationary the pin and socket arrangement enables the levers to be removed easily by inward displacement from their slots in the annular supporting member. The eccentric connection between each lever and its valve rod preferably comprises a yoke on the valve rod having a polygonal opening which receives a correspondingly shaped insert. The latter has an eccentric hole which receives a removable pivot pin on the lever. Adjustment of the angular position of the insert in the yoke serves to adjust the radial position of the valve rod relative to the lever and thereby regulate the extent to which the outlet is opened through the plunger action, the number of adjustments possible for each valve rod being equal to the number of sides on the insert. The supporting member for the levers may cooperat with one wall of the bowl to form a radial feed passage leading to the bowl interior.

These and other features of the invention will be better understood by reference to the accompanying drawings, in which,

Fig. 1 is a vertical sectional view of one form of the new bowl, in which part of the valve operating system is shown schematically;

' Fig. 2 is an enlarged horizontal sectional view of part of the bowl illustrated in Fig. 1, showing the eccentric connections between the valve rods;

Fig. 3 is a vertical sectional view of part of another form of the new bowl;

Fig. 4 is an exploded view of parts forming the eccentric connection between a lever and its valve rod in Fig. 3, and

' Fig. 5 is an enlarged perspective view of part 3 of the annular supporting member for the levers in Fig. 3.

Referring to Figs. 1 and 2, the numeral l designates a centrifugal bowl, which may be of the general form disclosed in my Patent No. 2,291,117. The bowl is rotatable on a vertical axis by a hollow spindle mounted in bear ngs in a stationary frame (not shown). The spindle I extends into a central hub Illa at the bottom of the bowl and contains a feed passage ||a which is closed at the upper end of the spindle. The bowl feed passes out of the spindle passage Ila through radial openings I lb and thence through radial bowl passages Hlb leading to the interior of the bowl.

The solids separated in the separating chamber I80 of the bowl are discharged intermittently through a series of peripheral outlet openings spaced circumferentially around the bowl, one of these openings being shown at Hid. Each opening Illd contains an insert |2 provided with an orifice IZa large enough to allow the expulsion of the larger separated solids. Within the bowl ar radially extending valve rods I3, one for each outlet orifice I2a, the outer ends of the rods I3 functioning as valves to alternately open and close the outlets. At its inner end, each valve rod I3 is provided with a strap or yoke I4 surrounding an eccentric I5 which is integral with or rigidly connected to a lever I6. The levers I6 are spaced circumferentially around the rotation axis of the bowl and extend generally radially from this axis. Each lever It with its eccentric i5 is pivotally mounted between a pair of supporting posts I! by means of a pivot pin I8 extending through the parts I5, I6 and H, the pivot pin being located below the center of the eccentric I5. The supporting posts I! extend upwardly from the bottom of the bowl ID and form therewith, in effect, an annular supporting member, the spaces between the several pairs of posts I! constituting circumferentially spaced radial slots of the supporting member in which the levers I6 are pivotally mounted on the eccentric pins I8.

A portion of each eccentric I5 is cut away, as shown at I9, to receive the rounded end 23a of an abutment screw threaded in the yoke M of the corresponding valve rod. Thus, downward movement of the inner end of each lever 6 causes a shoulder I5a, formed by the recess I9 in the eccentric I5, to move inwardly against the rounded end of the abutment screw 20 in the yoke l4, whereby the valve rod I3 is moved inwardly to open the corresponding outlet orifice I2a, it being understood that this action is opposed by the centrifugal force acting on each valve rod I3 and tendin to seat the outer end of the rod against the corresponding orifice l2a. Adjustment of the abutment screw 20 in the yoke I4 varies the position of the rounded end of the screw relative to the coacting cam face I5a, thereby varying the extent to which the corresponding outlet orifice |2a is opened by a given downward movement of the inner end of the lever I6.

It will be understood that each valve rod I3 is operated from a lever I6 through an eccentric connection as above described.

The annular supporting member formed by the posts I! on the bottom of the bowl also serves to support an annular plate 22 on top of the posts. The plate 22, in turn, supports an annular filter 23 concentric with the rotation axis. The filter 23 is supported between the plate 22 and a top 24 of the centrifugal bowl. A ring nut 25 secures the bowl top 24 to the main part of the bowl H), a packing ring 26 being located between the bowl I0 and its top 24. The liquid in the separating chamber Inc is displaced inwardly, while the valve rods |3 close the solids outlets I2a, and passes through the filter 23 which removes lighter solids from the liquid. The filtered liquid passes inwardly and upwardly from the filter 23 and over a level outlet 24a, the liquid finally discharging over the top of a neck 24b of the bowl top 24. When the valve rods I3 are moved inwardly by their levers Hi to permit escape of the separated solids through the peripheral outlets I2a, the liquid level in the bowl will move radially outward so as to cause a reverse flow through the filter 23.

On the upper end of the hollow driving spindle II is a cap nut 28, in the center of which is secured a post 29 carrying at its upper end an inverted cup 30 along which a cylindrical plunger 3| may slide. The plunger 3| is normally held in the upper position shown in Fig. 1 by means of a spring 32 located in the plunger and confined between the cup 30 and the upper end or head of the plunger. A sleeve 33 surrounds the plunger 3| and serves to guide it in its vertical movements on the post 29. A shoulder 3|a on the plunger is engageable with a stop 33a in the sleeve to limit upward movement of the plunger. The sleeve 33 is likewise supported by the posts H, the lower end of the sleeve being fitted tightly in the central opening of the annular plate 22. Accordingly, the sleeve 33 and the plunger 3| rotate with the bowl.

The plunger 3| is operated by a piston or plunger 35 movable in a stationary cylinder 36 which is mounted on a suitable frame (not shown) directly above the plunger. A coil spring 31 in the cylinder 38 serves to bias the piston 35 upwardly away from the head of the plunger 3|. Downward movement of the piston 35 is effected hydraulically by a fluid introduced into the cylinder from a pipe line 38 connected to a valve housing 39, The latter is provided with an exhaust line 48 and a pipe 4| which leads to a suitable pressure source. A valve 42 is reciprocable in the valve housing 39 to connect pipe 38 alternately to the exhaust line 40 and the pressure line 4|. The valve 42 has a stem 43 which is biased against the periphery of a cam 44 mounted on a shaft 45. The cam shaft 45 is driven from a worm 56 mounted on the bowl spindle II and meshing with a worm wheel 41 mounted on the cam shaft. It will be apparent that with this construction the valve 42 is reciprocated at a rate dependent upon the speed of rotation of the bowl I0, and in each complete cycle of the valve 42 the piston 35 will be moved down to depress the plunger 32 against the inner ends of levers Hi and then raised to cause upward movement of plunger 32. Downward movement of plunger 32 after it engages the levers l6 causes the eccentrics I5, acting through the yoke screws 29, to draw the valve rods inwardly from the outlets |2a; and upward movement of plunger 32 allows the valve rods to return to their outlet-closing positions under the action of centrifugal force.

Referring now to the embodiment of the invention illustrated in Figs. 3, 4 and 5, the centrifugal bowl 5|] is rotatable on a vertical axis by a hollow spindle 5| which extends into a hub 50a at the bottom of the bowl and contains a feed passage 5|a which is closed at the upper end of the spindle. The bowl feed passes out of the spindle passage la through radial openings 5lb and thence through radial passages 59b leading to the interior of the bowl, as will be described in greater detail presently.

On the upper end of the spindle 5| isa releasable member or nut 52 surrounded by a generally annular supporting member 5.3, which is seated on the bottom of the bowl 50, The latter may be formed with an annular shoulder c engaging a complementary shoulder on the member 53 to center the supporting member on the bottom of the bowl. In the bottom of the member 53 are radial channels 53a forming with the bowl bottom a series of passages communicating with the passages 50b and through which the feed'is deliveredinto the separating chamber of the bowl. The member 53 has a crown 531) provided with radial slots 53c spaced circumferentially around the member. A lever 54 is pivotally mounted in each slot 53c, the inner ends of the levers being disposed within the annular supporting member 53 and movable axially therein. Each lever is pivotally mounted in its slot 530 by means comprising lever trunnions 54a and a socket element 55 ofinverted U-shape. The socket elements 55, of which there is one for each lever, have their legs resting on the supporting member 53, where they are held between the crown 53b on the outside and an upstanding flange 53d on the inside.

The space 55a between the legs of each socket element is aligned with one of the radial slots 530 in the supporting member 53, andthe legs are provided with notches or sockets 55b which open into the interior of supporting member 53 and receive the lever trunnions 54a. The latter are rotatable in the sockets 55b to form the pivotal axis for the lever." The trunnions 54a are movable into their sockets 551) from within the annular member 53 and are held against the outer ends of the sockets by centrifugal force acting upon each lever. Also, while the socket elements 55 are held by centrifugal force against the crown 53b of the supporting member and may be considered as parts of this member, they can be easily removed from the bowl independently of supporting member 53.

Each lever 54 is provided with a radial slot 54b which receives a strap or yoke 51 at the inner end of a valve rod 58. Each valve rod is connected to a lever eccentrically with respect to the lever axis, by means of a pivot pin 59 which is offset from the trunnions 54a. Each pivot pin 59 extends through holes 540 at opposite sides of the lever slot 54b, and also through an intermediate hole 6011 which is eccentrically located in a polygonal insert 60 fitted in a correspondingly shaped opening 51a in the yoke 51. As shown, the inner end of each valve rod 58 is screwed on a threaded part 51b of its yoke. At the outer end of each rod is a valve element 58a, which is preferably made of a hardened material. The valve elements 58a are disposed in hollow inserts 6| mounted in openings in the peripheral part of the bowl 59, the inserts providing outlet openings Bid for the separated sludge. It will be understood that centrifugal force acting upon the valve rods 58 will tend to move the valve elements 58a outwardly and cause them to seat against the inserts 6| and thereby close the bowl outlets 6m. Due to the conical shape of the recess in the inserts 6|, the valve rods 58 are guided in their outward or valve-closing movements.

Mounted on top of the supporting member 53 is a tubular shaft 63 having a generally conical base portion 63a which receives and .is'centered by the crown 53b. The tubular shaft forms a sleeve projecting upwardly along the bowl axis and into the neck 64a of the removable top 6.4 of the bowl. Slidable axially within the tubular shaft 63 is a plunger 65 engageable at its lower end with the inner ends .of the levers 54. A spring 66 is coiled around the plunger but within the shaft 63, :the lower end of the spring engaging an internal shoulder 63b of the shaft, and the upper end of the spring engaging an external shoulder 65a .onthe plunger. The spring 66 therefore urges the plunger upwardly to engage its shoulder 65a with a removable stop 63c screwed in the upper end .of the tubular shaft. The plunger 65 may be depressed from outside the bowl in any suitable manner, against the spring 66 and the inner ends of levers 54, as by means of an operating member such as the piston 3-5 (Fig. 1) engaging the plunger head 65b. The interengaging parts of the plunger and its operating member 35 are preferably made of hardened metal to reduce the wear between the rotating and non-rotating parts, as is also the case in the Fig. 1 form.

The tubular shaft 63 also carries a series of spaced conical discs 68 located in the separating chamber of the bowl, the lowermost disc resting upon the conical base portion 63a of the tubular shaft. The shaft or sleeve 63 extends upwardly through central openings in the vconical discs and serves to position the discs centrally in the bowl. The lower discs extend downwardly and outwardly around the supporting crown 53b and are provided with slots 68a through which the valve rods 58 extend. At their outer ends, the radial feed passages 53a open into the bowl chamber below the conical discs and in the region of the outer periphery of the discs. Between the inner edges of the discs and the tubular shaft 63 are vertical passages 69 through which the liquid or lighter component separated between the discs is discharged upwardly into radial outlet passages 64b in the bowl neck. The solids separated between the discs are forced outwardly into the peripheral part of the bowl chamber, from which they are discharged through the outlets 6Ia each time the valve rods 58 are withdrawn upon actuation of the levers 54 by depression of plunger 65.

To adjust the valve rods 58, the bowl top 64 is removed and the tubular shaft or sleeve 63 is lifted from the bowl, together with the discs 68. The levers 54 and their valve rods 58 are then removed from the bowl, preferably with their socket elements 55 from which the levers may be easily withdrawn by sliding the trunnions 5411 out of their sockets 55b. Then the pin 59 is removed from each lever 54 and the yoke 51 withdrawn from the lever slot 541), after which the insert 60 is removed from its yoke and replaced in a different angular position, depending upon the desired adjustment. With a four-sided insert 60, as shown, four different adjustments are provided for the radial positioning of the valve rod relative to its lever. By increasing or decreasing the number of sides of the insert 60 (and of the yoke opening 51a), the number of adjustments may be increased or decreased. The manner of reassembly of the parts in the bowl will be apparent from the foregoing.

While the threaded connections 5112 may also serve for adjusting the valve rods 58 relative to their operating levers 54, I prefer to freeze these connections by soldering, or the like, once an initial adjustment has been made.

This application is a continuation-in-part of my application Serial No. 654,894, filed March 16, 1946, now Patent No. 2,488,746.

I claim: l

1. In a centrifuge having a centrifugal bowl provided with peripheral outlets, the combination of a generally annular supporting member mounted in the central part of the bowl concentrio to its axis and rotatable with the bowl, said member having circumferentially spaced radial slots, a plurality of levers pivotally mounted in the slots and having their inner ends movable axially within the supporting member, generally radial valve rods in the bowl, a yoke at the inner end of eachvalve rod, a member on each lever eccentric to the pivotal axis of the lever and surrounded by one of the yokes, an adjustable element movable within each yoke to vary the po-' sition of the valve rod relative to said pivotal axis of the lever whose eccentric member is surrounded by the yoke, said yoke, eccentric member and adjustable element forming an eccentric connection between the inner end of the valve rod and the lever, a valve element at the outer end of each rod adapted to close one of said outlets, a sleeve disposed axially of the bowl and rotatable therewith in alignment with the supporting member, a plunger rotatable with the sleeve and slidable axially therein relative to the levers for operating the levers to move the valve rods radially inward and thereby open said outlets, and an element outside the bowl and engageable with the plunger to actuate it.

2. A combination according to claim 1, in which said adjustable element is an adjustment screw in the yoke engageable with said eccentric member on the lever and operable to adjust the position of the valve rod relative to the lever.

3. A combination according to claim 1, in which said yoke has a polygonal opening,.said adjustable element being an insert fitted closely in said last opening and adjustable to difierent angular positions therein, the insert having an eccentric hole, and a pivot pin extending into said hole and into the lever.

4. A combination according to claim 1, in which the supporting member includes a removable socket element for each lever and having legs forming a radial slot, the legs also having notches opening into the interior of the supporting member, each lever having trunnions removably held in said notches.

5. A combination according to claim 1, in which the sleeve is seated on and centered by the supporting member, and comprising also a series of conical discs in the bowl supported by the sleeve and surrounding the sleeve, some of said discs having slots through which the valve rods extend.

GEORGE J. STREZYNSKI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,291,117 Strezynski July 28, 1942 FOREIGN PATENTS Number Country Date 129,573 Great Britain July 17, 1919 281,649 Great Britain Nov. 26, 1927 

